Air venting system



Feb. 13, 1968 1:). SKLAR 3,368,474

AIR VENTING SYSTEM Original Filed Sept. 14, 19 64 4 11141 11 1 /NVEN7'0R v v DA V/D S/(LAR ATTORNEY United States Patent M 3,368,474 AIRVENTING SYSTEM David Sklar, Nashua, N.H. Nashua Wood Products Inc.,Merrimack, N.H. 03054) Continuation of application Ser. No. 396,173,Sept. 14, 1964. This application Nov. 9, 1966, Ser. No. 593,224 2Claims. (Cl. 98115) ABSTRACT OF THE DISCLOSURE Apparatus for removingundesirable fumes and foreign matter from a work area in an enclosurewith little disturbance of the surrounding atmosphere. Inlet conduitsand outlet conduits communicating with the air exteriorly of theenclosure are positioned with their openings adjacent waste generatingareas in a manner to direct lateral flow of air across the wastegenerating areas. Air propelling means are housed in the outlet conduitsto pull air from the exterior through the inlet conduits across thewaste generating areas, and to exhaust the air laden with fumes andforeign matter to the exterior through the outlet conduits.

The present invention relates to the problem of exhausting wasteproducts, for example, in a manufacturing area. More particularly, theinvention relates to an air venting system and method for conducting airthrough and exhausting an area subject to the development of undesirablefumes, dust, chips, etc.

In a manufacturing plant it is frequently necessary to remove from anenclosed volume of air various waste products resulting frommanufacturing operations. A typical installation in the prior artemploys an exhaust fan to force air through an outlet in an enclosedvolume. This procedure results in the development of negative pressureswithin the enclosure. During the winter months severe heat losses aredeveloped because of the more or less constant flow of air from withoutthe enclosure through the enclosure. The result of the development ofnegative pressure within the enclosure relative to the pressure outsidecontributes to the difiiculty for example, of opening an outside door.Plant personnel have a tendency to leave the door open rather thanconstantly be faced with the problem of forcing it to open.

In the wintertime, a blast of cold air enters and immediately reducesthe temperature in the vicinity of the door. This results in exposingpersonnel to severe drafts and sharp temperature changes to present apersonnel health hazard. I

To overcome the draft problem in the prior art, air traps are introducedto provide an intermediate insulating pressure reduction chamber havingtwo entrances. In contrast, the present invention eliminates the needfor such a chamber.

Reduced pressure within the enclosure tends to fatigue personnel. In theprior art preheated air requiring special apparatus is introduced tooffset the negative temperature. In contrast, the present inventionobsoletes such a requirement.

In the summer months or in warm climates severe losses 3,368,474Patented Feb. 13, 1968 system draws upon the ambient heated air andexhausts the heated air at a very substantial rate. The entire volume ofenclosed air may be recirculated as much as 20 times per hour or more.Given an exhaust system capable of exhausting 26,000 cubic feet of airper minute, a volume of the order of 250,000 cubic feet can berecirculated completely in 6 minutes. This gives rise to an enormous andcontinuing heat loss. Conversely, in the summertime when the plant isair-conditioned, a substantial amount of cooled air is lost in such aprocess.

As distinct from the instant invention, prior art systems frequentlyintroduce special apparatus to recover exhausted processed air by use ofelaborate filter systems. In contrast, with the air venting system ofthe present invention, the exhaust function may be accomplished with airrecirculation for a given volume as little as once an hour.

It is therefore an object of the present invention to provide animproved air venting system for substantially reducing losses ofprocessed air.

Another object of the invention is to provide an improved air ventingsystem which automatically maintains a pressure balance between theatmosphere and an enclosed volume of air.

Yet another object of the invention is to provide an improved airventing system which enables the use of a heating system of reducedsize, complexity and cost for a given enclosed volume.

A further object of the invention is to provide an improved air ventingsystem for more efiiciently exhausting waste products.

In accordance with the invention, there is provided an air ventingsystem. This system includes a first ambient source of air at a firsttemperature and an enclosure means enclosing a volume of air at a secondtemperature differing from the first temperature. The enclosure means issurrounded by air from the first source at the first temperature. Aninlet conduit means is coupled to an inlet formed in the enclosure meanscommunicating with the first source for conducting air at the firsttemperature from the first source to a selected local evacuation region.The air of the first and second temperatures mix in the region.'0utletconduit means are coupled to an outlet formed in the enclosure means forconducting air from the evacuation region through the outlet. In thismanner, air from the first source is conducted through the region fromthe inlet to the outlet substantially without changing the secondtemperature of the enclosed volume of air.

Other and further objects of the invention will be apparent from thefollowing description, taken in connection with the accompanyingdrawing, and its scope will be pointed out in the appended claims.

In the drawing:

FIG. 1 is a schematic diagram of an air venting system embodying theinvention;

FIG. 2 is a schematic diagram of a modification of the embodiment inFIG; 1;

FIG. 3 is a front view partially in section of an inlet duct memberuseful in the invention; and

FIG. 4 is a plan view of a modification of the invention showing aplurality of flexible conduits in the vicinity of a waste producingmachine.

Referring now to the drawing and with particular reference to FIG. 1there is here illustrated a manufacturing plant 10 enclosing a volume ofair at a temperature T The plant 10 is surrounded by the atmosphere, theoutside ambient temperature being less than the temperature of the airwithin the plant 10, i.e. T T A machine 12 such as a saw which producessawdust in the course of its operation is positioned on the floor 13 ofthe plant 10. Atmospheric air at temperature T is admitted through aninlet duct 14 in the roof of the plant 10. The incoming air from theatmosphere may be, e.g., cold relative to the enclosed air and isconducted through an inlet conduit 15 through opening 16 in the vicinityof the machine 12. An output conduit 17 has an opening 18 in thevicinity of the machine 12 and couples the air to an outlet duct 19formed in the roof of the plant 10. An exhaust fan 20 is mounted in theduct 19 for exhausting air in the direction indicated by the arrow.

A machine 21 is shown in another location, for example, a drill oranother saw, having an inlet branch conduit 22 and an outlet branchconduit 23. The branch inlet conduit 22 is coupled, as shown, to asecond inlet duct 35. The conduit 22 may be coupled directly to the maininlet conduit 15. The branch outlet conduit 23 is coupled directly tothe main outlet conduit 17 to provide a parallel flow path forexhausting the machine 21. The inlet conduits for a plurality ofmachines may be coupled directly to a plurality of corresponding inletducts or may be parallel connected directly from a common inlet ductsuch as the duct 14. In like manner, the outlet or exhaust conduit maybe coupled to a plurality of outlet ducts. Broadly the totalcross-section of outlet should equal the total inlet cross-section.

The duct 19 is coupled to a conduit 31 which communicates with a cyclonefunnel chamber 32. The cyclone funnel 32 has an exhaust duct 34 andextends from a waste depository 33. An automatic damper control 36 ofconventional design is disposed in the inlet conduit 15 to control therate of fiow. The damper may be manually pre-set for a desired flowcondition and then varies automatically with the differential pressure.

In operation cold air at temperature T for example, F., enters the inletduct 14 and travels down the inlet conduit 15 in the direction indicatedby the arrow to the opening 16 of the conduit 15 which is located in thevicinity of the waste-producing region of the machine 12. The exhaustfan 20 creates a negative pressure region between the openings 16 and 18of the inlet and outlet conduits 16 and 17 respectively. Thus, the flowof air through the conduit 15 and out the conduit 17 is substantiallyforced by the operation of the exhaust fan 20, bounded by the conduits15 and 17 and the opening in the vicinity of the machine. Only arelatively small amount of the ambient enclosed air is drawn into theoutlet from the region where the air at the two temperatures tends tomix.

In the event that the temperature difference is quite great, forexample, 70, it is undesirable to expose the operators hands to theincoming cold air. Thus, the conduit openings 16 and 18 are so disposedas to minimize this exposure. Furthermore, the existence of a negativepressure region between the openings 16 and 18 produces a fiow of warmair by the operator into the outlet conduit 17.

The waste carrying air flows through the conduit 31 into the cyclonechamber 32. There the funnel shaped chamber causes the air to flow in avortex and recirculate within the chamber. The heavier waste materialfalls down through the opening at the bottom of the chamber 32 and isdeposited in the chamber 33.

The motion of the air from the inlet conduit to the outlet conduitprovides a controlled laminar flow of air which forces waste materialejected by the machine along a desired path, e.g., away from theoperator. In contrast, prior art systems provide only an exhaust conduitwhich is ineffective, for example, for chips ejected in a direction awayfrom the exhaust opening.

Referring now to FIG. 2, there is here illustrated a modification of thesystem in FIG. 1. It will be seen here that the inlet and outlet ductsmay be disposed at various locations in the enclosure walls. Thus, aninlet duct 24 is coupled to an inlet conduit 25 to an exhaust area of amachine 26. An outlet conduit 27 is coupled to an outlet duct 28. Theducts 24 and 28 are located relatively close to the ground. Thismodification may be more suitable for certain applications. Here againan exhaust fan may be disposed in the outlet duct 28. In such acircumstance, the circulating air through the duct 24, conduit 25,conduit 27 and outlet duct 28 is warmer than the enclosed ambient air.

In a further modification of the system in FIG. 1, shown in dashedlines, a duct 30 may be formed in the roof of the plant and coupledthrough a conduit 29 to the machine 26. It may be more convenient tolocate an inlet duct low relative to the ground and exhaust upwardlythrough the roof. Similarly, it may be more convenient to locate theoutlet duct low and the inlet duct relatively high.

Referring now to FIG. 3 there is here illustrated an inlet duct usefulin the present invention. A conical cover has a cylindrical extensionwall. The cover is supported by struts 39 attached to the cover and aninlet pipe 40. Air flows under the wall 38 into the pipe 40. Thisstructure avoids undue influence on air flow due to winds shifting indirection.

Referring now to FIG. 4 there is here illustrated a modification of thesystem particularly showing the venting structures at the wastegenerating region 48 of a machine 49. Thus, an inlet conduit 41 has apair of flexible inlet hoses 42 and 43 connected in parallel. The hoseshave funnelled extensions 44 and 45 to provide controlled air flow intoa selected region. An outlet conduit 46 has a funnelled extension 47 toreceive waste bearing air flow from the waste generating region. Forincoming cold air, the level of the outlet may be below that of one ormore of the inlets. The disposition of the flexible hoses may beadjusted to optimize waste removal. Of course the outlet conduit may beflexible as well to enable optimum positioning.

Because of the overhead structure, the embodiment of FIG. 1 appears tobe generally more applicable.

In an embodiment of the invention based on FIG. 1 which was actuallyconstructed and tested, the enclosed volume of air is 240,000 cubicfeet, the exhaust fan circulates 26,000 cubic feet per minute, twoexhaust conduits each have a cross-section of 6 square feet. The systemhas 30 inlet branches with a total cross-section of 12 square feet.Replacement of air is heated at the rate of 5,000 cubic feet per minutein contrast with 26,000 cubic feet per minute required with a prior artsystem.

With a prior art system a furnace capacity of 1,000,000 B.t.u. isrequired. In the present system only 200,000 B.t.u. capacity isrequired. Thus the original installation cost is reduced or more and theoperating cost by 80% or more.

It will be apparent from the foregoing description of the invention thatthe invention has broad application to air circulation systems whererelatively warm or cold air losses may be minimized.

While there has hereinbefore been described what is at presentconsidered to be preferred embodiments of the invention, it will beapparent to those of ordinary skill in the art that many and variouschanges and modifications may be made with respect to the embodimentsdescribed and illustrated without departing from the spirit of theinvention. It will be understood, therefore, that all such changes andmodifications as fall fairly within the scope of the present invention,as defined in the appended claims, are to be considered as a part of thepresent invention.

What is claimed is:

1. In a manufacturing building enclosing a volume of processed air, awaste disposal air-venting system for exhausting waste products in thevicinity of processing apparatus without unduly exhausting processedair, comprising:

inlet conduit means coupled to an inlet duct formed in the roof of saidbuilding for conducting unprocessed air from the atmosphere to aselected waste generating region, said unprocessed air and saidprocessed air mixing in said region, said inlet convalving means coupledto said inlet conduit means for duit means including an element soshaped and posiadjusting the velocity of air flow through said region.

tioned adjacent one side of said Waste generating 2 h System i l i 1 h iregion as to Provide lateral? flow through Said said conduit meansincluded a funnelled extension in Selected Waste generating 5 saidregion for shaping said air flow further to conoutlet conduit meanshaving substantially the same total 01 the motion of Waste materiaLcross-sectional area as said inlet conduit means v coupled to an outletduct formed in the roof of said References Cited building for conductingair from said region through said outlet duct, the opening of saidoutlet conduit 10 UNITED STATES PATENTS being positioned on the otherside of said waste gen- 2,209,054 7/ 1940 Bond et al. 98-1 eratingregion and substantially opposite said inlet 2,256,515 9/1941 Brueshaber98-415 X conduit m an 2,565,933 8/1951 Schneible 98-115 impeller meanscoupled to said outlet duct for produc- 2 579 401 12/1951 Schneible et L93 .115 ing a negative pressure in said selected waste gen- 15 2,874,6272/1959 Simmonds 115 erating region to pull air from said inlet conduit 2939 614 6/1960 Hill 98 115 X means through said region and said outletconduit means, to remove waste material from said region ROBERT OLEARYPrimary Examinen substantially without removing the ambient processedair thereby preventing any substantial change 20 M- AN AKA si n am n inthe temperature within said building; and

